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Delayed appearance of high altitude retinal hemorrhages.

Barthelmes D, Bosch MM, Merz TM, Petrig BL, Truffer F, Bloch KE, Holmes TA, Cattin P, Hefti U, Sellner M, Sutter FK, Maggiorini M, Landau K - PLoS ONE (2011)

Bottom Line: Significant negative (SpO₂ Beta: -0.4, p<0.001) and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003) correlations with hemorrhages were found.When closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes.The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland.

ABSTRACT

Background: Retinal hemorrhages have been described as a component of high altitude retinopathy (HAR) in association with altitude illness. In this prospective high altitude study, we aimed to gain new insights into the pathophysiology of HAR and explored whether HAR could be a valid early indicator of altitude illness.

Methodology/principal findings: 28 mountaineers were randomly assigned to two ascent profiles during a research expedition to Mt. Muztagh Ata (7546 m/24,751 ft). Digital fundus photographs were taken prior to expedition at 490 m (1,607 ft), during expedition at 4497 m (14,750 ft = base camp), 5533 m (18,148 ft), 6265 m (20,549 ft), 6865 m (22,517 ft) and 4.5 months thereafter at 490 m. Number, size and time of occurrence of hemorrhages were recorded. Oxygen saturation (SpO₂) and hematocrit were also assessed. 79% of all climbers exhibited retinal hemorrhages during the expedition. Number and area of retinal bleeding increased moderately to medium altitudes (6265 m). Most retinal hemorrhages were detected after return to base camp from a high altitude. No post-expeditional ophthalmic sequelae were detected. Significant negative (SpO₂ Beta: -0.4, p<0.001) and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003) correlations with hemorrhages were found.

Conclusions/significance: When closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes. The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding. Retinal hemorrhages should not be considered warning signs of impending severe altitude illness due to their delayed appearance.

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Ascent profile of both groups of climbers with indication of high camps and examination time points.
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pone-0011532-g001: Ascent profile of both groups of climbers with indication of high camps and examination time points.

Mentions: In this prospective, multidisciplinary study[5], [15], [16] 32 mountaineers were randomly assigned to two ascent profiles (Fig. 1) during an expedition to Mt. Muztagh Ata (7546 m/24,751 ft) in western China. Both ascent groups started the expedition at 3750 m/12,300 ft, then continued to base camp (BC1 = 4497 m/14,750 ft), camp 1 (C1 = 5533 m/18,148 ft), camp 2 (C2 = 6265 m/20,549 ft), camp 3 (C3 = 6865 m/22,517 ft) and to the summit (7546 m/24,751 ft) within 20 (group 1) and 19 (group 2) days. Average ascent rates were 190 and 200 m/d (623 and 656 ft/d), respectively (Fig. 1). Included were healthy, physically fit, experienced mountaineers of either gender and between 20 to 65 years of age without any ophthalmic pathology. They needed to have reached at least C2 and had to have available fundus photographs at second base camp (BC2) examination. Exclusion criteria were any type of ocular, cardiac or respiratory disease, or a history of high altitude pulmonary edema or high-altitude cerebral edema (HACE) after a rapid ascent (<3 nights) to altitudes below 3500 m. Time to every new examination camp (in days) was recorded from the start of the expedition above 3750 m/12,300 ft ( = time at altitude).


Delayed appearance of high altitude retinal hemorrhages.

Barthelmes D, Bosch MM, Merz TM, Petrig BL, Truffer F, Bloch KE, Holmes TA, Cattin P, Hefti U, Sellner M, Sutter FK, Maggiorini M, Landau K - PLoS ONE (2011)

Ascent profile of both groups of climbers with indication of high camps and examination time points.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040733&req=5

pone-0011532-g001: Ascent profile of both groups of climbers with indication of high camps and examination time points.
Mentions: In this prospective, multidisciplinary study[5], [15], [16] 32 mountaineers were randomly assigned to two ascent profiles (Fig. 1) during an expedition to Mt. Muztagh Ata (7546 m/24,751 ft) in western China. Both ascent groups started the expedition at 3750 m/12,300 ft, then continued to base camp (BC1 = 4497 m/14,750 ft), camp 1 (C1 = 5533 m/18,148 ft), camp 2 (C2 = 6265 m/20,549 ft), camp 3 (C3 = 6865 m/22,517 ft) and to the summit (7546 m/24,751 ft) within 20 (group 1) and 19 (group 2) days. Average ascent rates were 190 and 200 m/d (623 and 656 ft/d), respectively (Fig. 1). Included were healthy, physically fit, experienced mountaineers of either gender and between 20 to 65 years of age without any ophthalmic pathology. They needed to have reached at least C2 and had to have available fundus photographs at second base camp (BC2) examination. Exclusion criteria were any type of ocular, cardiac or respiratory disease, or a history of high altitude pulmonary edema or high-altitude cerebral edema (HACE) after a rapid ascent (<3 nights) to altitudes below 3500 m. Time to every new examination camp (in days) was recorded from the start of the expedition above 3750 m/12,300 ft ( = time at altitude).

Bottom Line: Significant negative (SpO₂ Beta: -0.4, p<0.001) and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003) correlations with hemorrhages were found.When closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes.The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland.

ABSTRACT

Background: Retinal hemorrhages have been described as a component of high altitude retinopathy (HAR) in association with altitude illness. In this prospective high altitude study, we aimed to gain new insights into the pathophysiology of HAR and explored whether HAR could be a valid early indicator of altitude illness.

Methodology/principal findings: 28 mountaineers were randomly assigned to two ascent profiles during a research expedition to Mt. Muztagh Ata (7546 m/24,751 ft). Digital fundus photographs were taken prior to expedition at 490 m (1,607 ft), during expedition at 4497 m (14,750 ft = base camp), 5533 m (18,148 ft), 6265 m (20,549 ft), 6865 m (22,517 ft) and 4.5 months thereafter at 490 m. Number, size and time of occurrence of hemorrhages were recorded. Oxygen saturation (SpO₂) and hematocrit were also assessed. 79% of all climbers exhibited retinal hemorrhages during the expedition. Number and area of retinal bleeding increased moderately to medium altitudes (6265 m). Most retinal hemorrhages were detected after return to base camp from a high altitude. No post-expeditional ophthalmic sequelae were detected. Significant negative (SpO₂ Beta: -0.4, p<0.001) and positive (hematocrit Beta: 0.2, p = 0.002, time at altitude Beta: 0.33, p = 0.003) correlations with hemorrhages were found.

Conclusions/significance: When closely examined, a very large amount of climbers exhibit retinal hemorrhages during exposure to high altitudes. The incidence of retinal hemorrhages may be greater than previously appreciated as a definite time lag was observed between highest altitude reached and development of retinal bleeding. Retinal hemorrhages should not be considered warning signs of impending severe altitude illness due to their delayed appearance.

Show MeSH
Related in: MedlinePlus